1. Field of the Invention
This invention relates to fluid flow-control valves and, more particularly, automatic flow-control valves for hydronic systems.
2. Description of the Prior Art
The prior art is replete with flow-control valves of various degrees of sophistication, from manual valves to automatic valves utilizing spring-loaded pistons responding to pressure variations to open or close exit ports and thus to control fluid flow. All of the automatic flow-control valves of the prior art have suffered from turbulent fluid flow therethrough. Such turbulent flow has resulted in hunting or chattering of the flow control piston, which is a noisy and destructive phenomenon, and has further, made it necessary to use a plurality of different valves to cover a wide range of differential pressures across the control valves. The problem has been particularly evident at low differential pressures.
Accordingly, it is a general object of this invention to overcome the disadvantages of the prior art, as described hereinbefore.
It is a more specific object of this invention to provide a flow-control valve which provides accurate flow control over a wide range of operating pressures, as represented by a wide range of differential pressures across such control valve.